The Andhra Pradesh police has sounded a high alert on its border along with Orissa after the latest attack by the rebels of Communist Party of India - Maoists in Malkangiri district of Orissa, in which 21 policemen were reportedly killed.

A senior police official in Hyderabad said that all the sensitive police stations in the tribal and forest areas adjoining Orissa have been put on high alert and asked to maintain a tight vigil.

The Andhra Pradesh police had anticipated an attack by Maoists in the state but the CPI-Maoist cadres chose policemen in Orissa as their target.

Sources said that the top police brass in AP has asked the Greyhounds to maintain a low-profile for some time and also to gather more intelligence about the movement of Naxals.